SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f774bf43c2e948953627d6c49056b30f5a0259ad1d7db1d2a63ffe73c7a197bf' 
  AND token = 'XKggiYKhM488wfwjUeb5sGefhs53f+MMklilOWvwlKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}